/* Handles all data updates of the application i.e. movement across screen, decreasing time etc.,  NO rendering

	e.g.

	App::OnLoop()
	{
		for (int i < 0; Entity::Entity[i] != 0 && i < Entity::EntityList.size(); i++ ) {
		Entity::Entity[i]->OnLoop();  // Entity::OnLoop() checks for movement, location, speed etc.
		}

		// Other objects' data that may be changing i.e. animation state
	}

*/